French President Nicolas Sarkozy said that he has put the southwestern region of the country on its highest-level terror alert following a shooting outside a Jewish school that left four dead.
In comments from Paris, Sarkozy added it is "obvious" the attack in the city of Toulouse was anti-Semitic in nature. He also said he believes the same gunman was responsible for two other shootings last week that left three French servicemen dead.
On March 12, an unknown gunman shot dead a soldier in Toulouse, while on March 16, two more soldiers were killed and one seriously wounded near a military base about 50 kilometers away from Toulouse. All the slain soldiers were of North African or Caribbean origin.
Police reported that the same high-caliber pistol and motorbike were used in all three attacks. They suspect the attacker is an experienced marksman.
In addition, police in Paris have opened an investigation into threatening letters received by two synagogues in the capital. Authorities are making no links between the shootings and the letters.
During a visit to Toulouse, Sarkozy called the March 19 shooting a "national tragedy."
"That crazy people are able to do this is a tragedy," he said. "It reminds us about the depth of human nature -- of human beings who are human beings in name only. [They] don't follow the practices that respect the dignity of life, which should be sacred."
Israeli Prime Minister Benjamin Netanyahu called the killings "despicable murder."
"Today we had a savage crime in France that gunned down French Jews, among them children. It's too early to say what the precise background for this act of murder is, but I think that we can't rule out that there was a strong murderous anti-Semitic motive here," Netanyahu said. "I am sure that Nicolas Sarkozy, the president of France, and his government will do their utmost to find the killer and we in Israel will do everything to help them in this task."
Israel announced that the four victims of the shooting will be buried in Israel, in accordance with their families' wishes.
The victims have been identified as Rabbi Jonathan Sandler, 30; his sons, Gabriel and Arieh, ages 4 and 5; and 7-year-old Miriam Monsonego, daughter of the school's principal.
The current French presidential election campaign has been put on hold in a show of national unity in the wake of the tragedy. Sarkozy said he would suspend campaign activities at least until March 21.
Socialist candidate Francois Hollande, who also visited Toulouse on March 19, said, "We must do everything to ensure that acts of anti-Semitism or racism are met with a firm and common response from the whole republic."
Far-right candidate Marine Le Pen also canceled campaigning, saying it is right to "suspend politics as a sign of compassion and solidarity."
European and U.S. leaders have condemned the shooting, as has the Vatican.
Security around synagogues and other Jewish institutions has been stepped up in New York, Sweden, and other places.
With reporting by Reuters, AFP, and dpa